Synopsis
Low: libssh4 security and bug fix update
Type/Severity
Security Advisory: Low
Topic
Updated libssh4 packages that fix one security issue and two bugs are now
available for Red Hat Enterprise Linux 7.
Red Hat Product Security has rated this update as having Low security
impact. A Common Vulnerability Scoring System (CVSS) base score, which
gives a detailed severity rating, is available from the CVE link in the
References section.
Description
The libssh4 packages provide a library that implements the SSH2 protocol.
A flaw was found in the way the kex_agree_methods() function of libssh4
performed a key exchange when negotiating a new SSH session. A
man-in-the-middle attacker could use a crafted SSH_MSG_KEXINIT packet to
crash a connecting libssh4 client. (CVE-2015-1782)
This update also fixes the following bugs:
- Previously, libssh4 did not correctly adjust the size of the receive
window while reading from an SSH channel. This caused downloads over
the secure copy (SCP) protocol to consume an excessive amount of memory.
A series of upstream patches has been applied on the libssh4 source code to
improve handling of the receive window size. Now, SCP downloads work as
expected. (BZ#1080459)
- Prior to this update, libssh4 did not properly initialize an internal
variable holding the SSH agent file descriptor, which caused the agent
destructor to close the standard input file descriptor by mistake.
An upstream patch has been applied on libssh4 sources to properly
initialize the internal variable. Now, libssh4 closes only the file
descriptors it owns. (BZ#1147717)
All libssh4 users are advised to upgrade to these updated packages, which
contain backported patches to correct these issues. After installing these
updated packages, all running applications using libssh4 must be restarted
for this update to take effect.
Solution
Before applying this update, make sure all previously released errata
relevant to your system have been applied.
For details on how to apply this update, refer to:
https://access.redhat.com/articles/11258
Affected Products
-
Red Hat Enterprise Linux Server 7 x86_64
-
Red Hat Enterprise Linux Server - Extended Update Support 7.6 x86_64
-
Red Hat Enterprise Linux Server - Extended Update Support 7.5 x86_64
-
Red Hat Enterprise Linux Server - Extended Update Support 7.4 x86_64
-
Red Hat Enterprise Linux Server - Extended Update Support 7.3 x86_64
-
Red Hat Enterprise Linux Server - AUS 7.6 x86_64
-
Red Hat Enterprise Linux Workstation 7 x86_64
-
Red Hat Enterprise Linux Desktop 7 x86_64
-
Red Hat Enterprise Linux for IBM z Systems 7 s390x
-
Red Hat Enterprise Linux for IBM z Systems - Extended Update Support 7.6 s390x
-
Red Hat Enterprise Linux for IBM z Systems - Extended Update Support 7.5 s390x
-
Red Hat Enterprise Linux for IBM z Systems - Extended Update Support 7.4 s390x
-
Red Hat Enterprise Linux for IBM z Systems - Extended Update Support 7.3 s390x
-
Red Hat Enterprise Linux for Power, big endian 7 ppc64
-
Red Hat Enterprise Linux for Power, big endian - Extended Update Support 7.6 ppc64
-
Red Hat Enterprise Linux for Power, big endian - Extended Update Support 7.5 ppc64
-
Red Hat Enterprise Linux for Power, big endian - Extended Update Support 7.4 ppc64
-
Red Hat Enterprise Linux for Power, big endian - Extended Update Support 7.3 ppc64
-
Red Hat Enterprise Linux for Scientific Computing 7 x86_64
-
Red Hat Enterprise Linux Server from RHUI 7 x86_64
-
Red Hat Enterprise Linux EUS Compute Node 7.6 x86_64
-
Red Hat Enterprise Linux EUS Compute Node 7.5 x86_64
-
Red Hat Enterprise Linux EUS Compute Node 7.4 x86_64
-
Red Hat Enterprise Linux EUS Compute Node 7.3 x86_64
-
Red Hat Enterprise Linux Server - AUS 7.4 x86_64
-
Red Hat Enterprise Linux Server - AUS 7.3 x86_64
-
Red Hat Enterprise Linux for Power, little endian 7 ppc64le
-
Red Hat Enterprise Linux for Power, little endian - Extended Update Support 7.6 ppc64le
-
Red Hat Enterprise Linux for Power, little endian - Extended Update Support 7.5 ppc64le
-
Red Hat Enterprise Linux for Power, little endian - Extended Update Support 7.4 ppc64le
-
Red Hat Enterprise Linux for Power, little endian - Extended Update Support 7.3 ppc64le
-
Red Hat Enterprise Linux for Power, little endian - Extended Update Support 7.2 ppc64le
-
Red Hat Enterprise Linux Server - TUS 7.6 x86_64
-
Red Hat Enterprise Linux Server - TUS 7.3 x86_64
-
Red Hat Enterprise Linux Server (for IBM Power LE) - Update Services for SAP Solutions 7.6 ppc64le
-
Red Hat Enterprise Linux Server (for IBM Power LE) - Update Services for SAP Solutions 7.4 ppc64le
-
Red Hat Enterprise Linux Server (for IBM Power LE) - Update Services for SAP Solutions 7.3 ppc64le
-
Red Hat Enterprise Linux Server - Update Services for SAP Solutions 7.6 x86_64
-
Red Hat Enterprise Linux Server - Update Services for SAP Solutions 7.4 x86_64
-
Red Hat Enterprise Linux Server - Update Services for SAP Solutions 7.3 x86_64
Fixes
- BZ - 1147717 - free'ing a not-connected agent closes STDIN
- BZ - 1199511 - CVE-2015-1782 libssh4: Using SSH_MSG_KEXINIT data unbounded
CVEs
References
Vulmon